SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46b56626384151065e63470cc9dc9ff9f118840cc02f2e9cc3e174c98e6e87aa' 
  AND token = 'QGCWdaFhttNxxNQ1dMelPe8eiDkwqmYPATIlh9kaSmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}